"The Anarchist's Advocate" is a history of radical dissent, police power, and the struggle for civil liberties in the United States during the early twentieth century, with particular attention to World War I and the ensuing Red Scare. The narrative centers on New York anarchists, their confrontations with the new surveillance state, and their relationship with lawyer Harry Weinberger, who represented them in criminal trials, Ellis Island deportation proceedings, and in two landmark cases before the U.S. Supreme Court. When the United States entered World War I, virtually no one in America--least of all the anarchists themselves--actually believed that the Constitution offered the slimmest protection for alien radicals and their political ideas. Through research in Harry Weinberger's legal papers, the papers of federal officials, government documents, and the writings of Weinberger's radical associates, "The Anarchist's Advocate" tells the story of how and why that began to change.